Add ZVMA pre/post script recipe + env-dump examples

Adds a Kubernetes-ZVMA companion to the existing Windows-ZVM recipe:

- scripts/examples/zerto-zvma-send.ps1 - Zerto-side sender for both
  pre and post phases, packages the Zerto* env vars into a structured
  JSON body and POSTs to a {phase}-templated webhook URL.
- scripts/examples/zerto-receiver-notify.ps1 - server-side receiver
  that posts a Slack/Teams notification, with phase-aware formatting
  and ZertoForce highlighted on pre.
- scripts/examples/zerto-receiver-vm-healthcheck.ps1 - server-side
  receiver that pings + port-probes each VM in VmDisplayNames after
  failover and writes a per-run JSON report.
- scripts/examples/send-env-vars.ps1 + save-env-vars.ps1 - generic
  env-dump client/receiver pair (the diagnostic that surfaced what
  the ZVMA scripts-service container exposes).
- docs/recipes/zerto-zvma-pre-post.md - full walkthrough mirroring
  the existing Windows-ZVM recipe's structure.
- README.md and docs/README.md - link the new recipe and examples.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/examples/zerto-receiver-notify.ps1

@@ -0,0 +1,90 @@
+<#
+.SYNOPSIS
+    Webhook-server-side receiver: posts a Slack/Teams notification when a VPG
+    fires its pre or post recovery script.
+
+.DESCRIPTION
+    Reads the JSON body from stdin (the payload sent by zerto-zvma-send.ps1),
+    builds a phase-aware message, and posts it to an Incoming Webhook URL.
+
+    The message highlights:
+      - VPG name + operation type (Test / Failover / Move / ...)
+      - Whether ZertoForce was set (only relevant pre)
+      - VM display names included in the run
+      - Phase (pre vs post) so you can see the bracketing in chat
+
+    Wire up two endpoints:
+        /hook/zerto-pre   -> this script with -Phase pre  (pass via args)
+        /hook/zerto-post  -> this script with -Phase post
+
+    Or one endpoint per phase, each pointing at this script. The script reads
+    `phase` from the JSON body, so the -Phase param is optional.
+
+.NOTES
+    Compatible with:
+      - Slack Incoming Webhooks (posts {"text": "..."})
+      - Teams legacy connector "Incoming Webhook" (same body shape)
+      - Discord webhooks (use ?wait=true for body, but text is "content" not
+        "text" - tweak below)
+
+    Endpoint config:
+        ExecutorType:   WindowsPowerShell or PowerShell 7
+        ScriptPath:     C:\scripts\zerto-receiver-notify.ps1
+        DataPassing:    [x] Stdin JSON
+        ResponseMode:   async  (we don't need to block the VPG on a chat post)
+#>
+
+[CmdletBinding()]
+param(
+    [string] $NotifyUrl = $env:NOTIFY_URL  # set on the Webhook Server host, or hardcode below
+)
+
+$ErrorActionPreference = 'Stop'
+
+if (-not $NotifyUrl) {
+    # Fall back to a hardcoded URL if NOTIFY_URL env var isn't set.
+    # Replace with your Slack/Teams Incoming Webhook URL.
+    $NotifyUrl = 'https://hooks.slack.com/services/REPLACE/ME/HERE'
+}
+
+$body = [Console]::In.ReadToEnd()
+if ([string]::IsNullOrWhiteSpace($body)) {
+    Write-Error 'Empty stdin - expected JSON body from the webhook server.'
+    exit 2
+}
+$p = $body | ConvertFrom-Json
+
+$z     = $p.zerto
+$phase = if ($p.phase) { $p.phase } else { 'unknown' }
+$op    = if ($z.operation) { $z.operation } else { 'unknown' }
+
+# Pick an icon based on operation. Test is benign; Failover/Move are real.
+$icon = switch ($op) {
+    'Test'     { ':test_tube:' }
+    'Failover' { ':rotating_light:' }
+    'Move'     { ':truck:' }
+    default    { ':information_source:' }
+}
+
+$forceTag = if ($phase -eq 'pre' -and $z.force -eq 'Yes') { '  *(FORCE)*' } else { '' }
+
+$lines = @(
+    "$icon  *Zerto $op* - phase: ``$phase``$forceTag"
+    "VPG: ``$($z.vpgName)``"
+    "VMs: ``$($z.vmDisplayNames)``"
+    "Hypervisor mgr: ``$($z.hypervisorManagerIP):$($z.hypervisorManagerPort)``"
+    "Captured: $($p.capturedAt)  (from $($p.host))"
+)
+$text = $lines -join "`n"
+
+$payload = @{ text = $text } | ConvertTo-Json -Compress
+
+try {
+    Invoke-RestMethod -Method Post -Uri $NotifyUrl `
+        -ContentType 'application/json' -Body $payload -TimeoutSec 10 | Out-Null
+    Write-Host "[$phase] notified $op for VPG '$($z.vpgName)'"
+}
+catch {
+    Write-Error "Notification post failed: $($_.Exception.Message)"
+    exit 1
+}